#封装函数

def convert_currency(im,er):
    out = im * er
    return out
USD_VS_RMB = 6.77

def main():

  currency_str_value = input('请输入带单位的金额:')

  unit = currency_str_value[-3:]

  if unit == 'CNY':
      exchange_rate = 1 / USD_VS_RMB
  elif unit == 'USD':
      exchange_rate = USD_VS_RMB
  else:
      exchange_rate = -1
  if exchange_rate !=-1:
      in_money = eval(currency_str_value[:-3])
      Qut_money = convert_currency(in_money,exchange_rate)
      print('兑换后金额:',Qut_money,'$')
  else:
      print('不支持该货币~!')

if __name__ == '__main__':
    main()